High voltage electrical distribution equipment may generate an electric field gradient that may result in corona. Corona may result when the electric field in air is strong enough to strip some electrons from the atoms and cause the air to become a conductive plasma. In particular, when a high voltage object includes surfaces having a small curvature or sharp points and/or edges, the electric field strength may be high enough to generate a corona.
Corona rings, which may also be referred to as field stress grading rings, are electrically conductive rings, or parts thereof that may be placed at the high voltage end of electrical insulators and may be positioned substantially orthogonally relative to the conductor. The corona rings may function to modify the shape of the electric field intensity so that the peak rate of change of field on the electrical insulator is reduced to a level that is below the breakdown voltage of the surrounding air.
Distribution and substation equipment used to supply electrical power have used wildlife protection to prevent wildlife from simultaneously contacting energized and grounded surfaces and/or adjacent phases. When such contact occurs, short circuits and consequent power outages frequently may be the result. The wildlife protection may be typically applied to an equipment bushing or lightning arrester of the distribution or substation equipment. For adequate protection, a number of presently available wildlife guards have also required an insulated or covered wire between the bushing and arrester.
Available wildlife guards have posed problems because they only attempt to deter the animal from simultaneously touching a grounded surface and an energized surface. Such guards do nothing to prevent an animal from climbing on the equipment entirely. As a result, because the animal is not deterred from staying away from the equipment entirely, the animal may still find a way to simultaneously touch energized and grounded surfaces. Additionally, the animals, particularly squirrels, have a tendency to chew on prior art wildlife guards. As such, effective wildlife guards are desired.
Multiple different types of devices, each directed to addressing different issues that arise in electrical power distribution systems may, in aggregate, increase the overall system complexity and thus may be costly.